Various devices can be utilized in a well that traverses a hydrocarbon-bearing subterranean formation. In many instances, it may be desirable to divide a subterranean formation into zones and to isolate those zones from one another in order to prevent cross-flow of fluids from the rock formation and other areas into the annulus. There are in-flow control devices that may be used to balance production, for example, to prevent all production from one zone of the well. Without such devices, the zone may produce sand, be subject to erosion, water breakthrough, or other detrimental problems.
For example, a packer device may be installed along production tubing in the well. Expansion of an elastomeric element may cause the packer to expand and restrict the flow of fluid through an annulus between the packer and the tubing. Packers are set when the completion is run in. However, there are other instances when one or more zones of a well may need to be separated or blocked off during remedial work.
Zones may also be separated by one or more screens. For example, screens may be used to control the migration of formation sands into production tubulars and surface equipment, which can cause washouts and other problems, particularly from unconsolidated sand formations of offshore fields. In a gravel pack, fluids may be used to carry gravel from the surface and deposit the gravel in the annulus between a sand-control screen and the wellbore. This may help hold formation sand in place. Formation fluid can flow through the gravel, the screen, and into the production pipe. Sometimes, the screens become damaged due to gravel pressure, erosion, or other forces or environmental conditions.
There are also in-flow control devices (ICD) that may be used to control undesired fluids from entering into production tubing. For example, an in-flow control device may be installed and combined with a sand screen in an unconsolidated reservoir. The reservoir fluid runs from the formation through the sand screen and into the flow chamber, where it continues through one or more tubes. The tube lengths and their inner diameters are generally designed to induce the appropriate pressure drop to move the flow through the pipe at a steady pace. The in-flow control device serves to equalize the pressure drop. The equalized pressure drop can yield a more efficient completion. Other in-flow control devices may be referred to as autonomous in-flow control devices (AICD). An AICD may be used when production causes unwanted gas and/or water to migrate to the wellbore. An AICD may be used when uneven production distribution results due to pressure drop in the tubing. An AICD works initially like a passive ICD, yet it restricts the production of water and gas at breakthrough to minimize water and gas cuts.
Although packers, screens, and in-flow control systems are often run in on the completion, there are instances when revision or remedial work needs to be done on the components after they have already been set.